#!/usr/bin/perl -w

use strict;
use constant DLE=>0x10;
use vars qw($DLE_C);
$DLE_C = chr(DLE);

my $msg = pack ("CCCCC", 0x31, 0x32, 0x10, 0x10, 0x33);
# match $dle's expanded, replacement is not expanded ?
$msg =~ s/$DLE_C$DLE_C/$DLE_C/g;
printf ("%02x " x length($msg) . "\n", unpack ("C*", $msg));

##</code><code>##

$msg =~ s/(\x{$dle})\x{$dle}/$1/g;